0000000000061693
AUTHOR
Petteri Pusa
4He+Ni elastic scattering near the Coulomb barrier and optical model parameters
Cross sections for the elastic scattering system of 4He+Ni have been investigated. Natural nickel was bombarded by 4He ions in the laboratory energy range of 3.0–14.3 MeV and the intensity of helium backscattering through laboratory angles of 96°, 117°, and 137° was observed. From measured yield data, the cross sections were extracted for the direct Ni(4He,4He)Ni scattering process as well as for the inverse recoil scattering process 4He(58Ni,4He)58Ni by calculating the kinematical reversal of the reaction. The experimental helium scattering angles convert to helium recoil angles of 20°, 30°, and 40°, and the incident helium ion energies to 43.5–207 MeV for incident 58Ni ions in the reverse…
RBS and ERD cross-sections and optical model parameters for the analysis of lithium, boron and nickel
Abstract Elastic scattering cross-sections for RBS analysis of nickel by 7 Li and 11 B ion backscattering near the Coulomb barrier have been determined. The lithium ion measurements were performed in the energy range of 8–15 MeV at the laboratory angles of 115° and 135°. For boron ions the energies between 14 and 24 MeV and scattering angles of 89°, 110° and 130° were used. For the analysis of lithium and boron by ERD the scattering cross-sections have been calculated by kinematically reversing the backscattering process. The calculated 58 Ni ion energies thus varied between 65 and 125 MeV for lithium and between 75 and 130 MeV for boron recoils. For the Li + Ni and B + Ni systems the thres…
Si self-diffusion in cubic B20-structured FeSi
Self-diffusion of implanted 31Si in the e-phase FeSi (cubic B20-structure) has been determined in the temperature range 660–810 °C using the modified radiotracer technique. With an activation enthalpy of 2.30 eV and a pre-exponential factor of 15×10−8 m2 s−1 the silicon diffusivity was found to be slightly slower than Ge impurity diffusion in FeSi. This difference is proposed to originate from attractive elastic interactions prevailing between the slightly oversized Ge atoms and the Si sublattice vacancies. The results confirm the argument that 71Ge radioisotopes may be used to substitute the short-lived 31Si radiotracers when estimating self-diffusion in silicides.